Reliability and 3D Modeling of Flexible Walls with EPS Inclusion
Publication: International Journal of Geomechanics
Volume 17, Issue 7
Abstract
Lengthy retaining walls are typically required in several geotechnical applications. Compacted soil is the classic backfill behind such walls, yet soil has a high unit weight that imposes large lateral loads and may lead to outsized wall dimensions. Geofoam or foam made of expanded polystyrene (EPS) can substitute the soil backfill due to its light weight and high compressibility and can reduce the lateral static loads imposed on walls. In this paper, EPS mechanical properties were measured in addition to the interface friction between this geomaterial and other materials, such as sand and concrete. A reliability analysis was conducted to develop the partial resistance factors required for the main EPS properties. Using a three-dimensional (3D) numerical analysis, the reliable EPS properties were used in the hardening soil constitutive model to simulate flexible walls with EPS inclusions of various thicknesses. Analysis outcomes were verified against measurements from a physical prototype and were also compared with results from the literature. From the main outcomes, the lateral pressure on flexible walls can be significantly reduced by up to 25% using a relatively thin EPS inclusion, and design charts for the reduction in the lateral pressure are provided.
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Acknowledgments
This study is part of the ongoing research project “development of EPS geofoam to improve infrastructure efficiency,” which is funded by the National Science and Technology Development Fund (STDF) Project Number 12629. The authors are grateful to the British University in Egypt (BUE), which hosted the tests in its laboratories and provided the license for PLAXIS 3D. Special thanks go to Professor Hani Amin (BUE) for help and funds provided during the prototype instrumentation and to Ahmed Youssef and Fawzy Mohamed for their help during testing.
References
AbdelSalam, S. S., and Azzam, S. A. (2016a). “EPS resistance factors and applications on flexible walls.” ” Proc., Geo-China 2016: Geosynthetic Civil Infrastructure, Disaster Monitoring, and Environmental Geotechnics, ASCE, Reston, VA, 131–138.
AbdelSalam, S. S., and Azzam, S. A. (2016b). “Reduction of lateral pressures on retaining walls using geofoam inclusion.” Geosynth. Int., 23(6), 395–407.
AbdelSalam, S. S., Baligh, F. A., and El-Naggar, H. M. (2014b). “A database to ensure reliability of bored pile design in Egypt.” J. Geotech. Eng., 168(2), 131–143.
AbdelSalam, S. S., Suleiman, M. T., and Sritharan, S. (2014a). “Modeling load-transfer behavior of H-piles using direct shear and penetration test results.” Geotech. Test. J., 37(4), 1–15.
Athanasopoulos, A. Z., Lamote, K., and Athanasopoulos, G. A. (2012). “Use of EPS geofoam compressible inclusions for reducing the earthquake effects on yielding earth retaining structures.” Soil Dyn. Earthquake Eng., 41, 59–71.
Birhan, A. (2014). “Effect of confinement and temperature on the behavior of EPS geofoam.” Ph.D. dissertation, Syracuse Univ., Syracuse, NY.
Brinkgreve, R. B., Broere, W., and Waterman, D. (2006). Plaxis 2D software manual version 8, Delft Univ. of Technology and Plaxis Inc., Delft, Netherlands.
Brinkgreve, R. B. J., Kumarswamy, S., and Swolfs, W. M. (2015). Plaxis 3D reference manual anniversary edition version 1, Plaxis bv, Delft, Netherlands.
Deng, A., and Xiao, Y. (2010). “Measuring and modeling proportion-dependent stress-strain behavior of EPS-sand mixture.” Int. J. Geomech., 214–222.
EPS Alliance. (2012). “Expanded polystyrene geofoam applications and technical data.” ⟨http://www.cellofoam.com/BuildingProducts/epsgeofoam.html⟩ (Nov. 17, 2016).
Ertugrul, O. L., and Trandafir, A. C. (2013). “Lateral earth pressures on flexible cantilever retaining walls with deformable geofoam inclusion.” Eng. Geol., 158, 23–33.
FLAC 2D [Computer software]. Itasca Consulting Group, Minnesota.
Horvath, J. S. (1994). “Expanded polystyrene (EPS) geofoam: An introduction to material behavior.” Geotext. Geomembr., 13(4), 263–280.
Horvath, J. S. (2004). “Lessons learned from failure: EPS geofoam.” Geotech. Fabrics Rep., 21(8), 34–37.
Itasca Consulting Group. (2008). FLAC: Fast Lagrangian analysis of continua, version 6, Minneapolis.
Miller, I., and Miller, M. (2004). John E. Freund’s mathematical statistics with applications, 7th Ed., Pearson Prentice-Hall, Upper Saddle River, NJ.
Negussey, D., and Sun, M. (1996). “Reducing lateral pressure by geofoam (EPS) substitution.” Proc., Int. Symp. on EPS Construction Method, Japanese Geotechnical Society, Tokyo, 201–211.
Padade, H., and Mandal, J. (2014). “Expanded polystyrene-based geomaterial with fly ash.” Int. J. Geomech., 06014013.
PLAXIS 3D Anniversary Edition [Computer software]. Plaxis bv, Delft, Netherlands.
Rankine, W. (1857). “The stability of loose earth.” Philos. Trans. R. Soc. London, 147, 9–27.
van Dorp, T. (1988). “Expanded polystyrene foam as light fill and foundation material in road structures.” Int. Congress on Expanded Polystyrene, Milan, Italy.
Wadsworth, H. M. (1990). Handbook of statistical methods for engineers and scientists, McGraw-Hill, New York.
Yoon, G., Yoon, Y., and Kim, H. (2007). “Determination of characteristic values for marine clay.” Proc., ISGSR2007 First Int. Symp. on Geotechnical Safety and Risk, Shanghai Tongji Univ., Shanghai, China.
Zarnani, S., and Bathurst, R. J. (2007). “Experimental investigation of EPS geofoam seismic buffers using shaking table tests.” Geosynth. Int., 14(3), 165–177.
Zarnani, S., and Bathurst, R. J. (2009). “Influence of constitutive model on numerical simulation of EPS seismic buffer shaking table tests.” Geotext. Geomembr., 27(4), 308–312.
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© 2016 American Society of Civil Engineers.
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Received: Mar 22, 2016
Accepted: Sep 27, 2016
Published online: Dec 2, 2016
Discussion open until: May 2, 2017
Published in print: Jul 1, 2017
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